Through the early 1600s, physicians believed there were two kinds of blood, one made by the liver and one by the heart...
Did you ever hear that blood is actually blue inside your body, but turns red instantly on contact with air? Learn more on this Moment of Science.
There aren't too many of us who think leeches are cool--but they are still used in medicine, and now there is even a mechanical leech.
Why can’t leaves change colors, stay on their trees, and change back to green again when spring comes?
Swollen Hands and Walking, on today’s Moment of Science. Do your hands swell up when you walk? If they do, it probably has to do with your circulation. The circulatory system is a one way street. Blood flows away from the heart in the arteries, down the arms and legs then back up to the [...]